Date:         Sat, 4 Apr 2009 17:58:07 -0700
Reply-To:     David Kao <dtkao0205@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Kao <dtkao0205@YAHOO.COM>
Subject:      Re: LVC: Learning Electricity & Testers
In-Reply-To:  <59145.56532.qm@web45302.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Whether you use a cheap or an expensive high end analog or digital
Volt/Ohm/Amp meter there are two easily made mistakes to avoid when
using it. Any of the two mistakes could cause damage to the meter
and the circuit being tested.

When use the Ohm meter functions you want to make sure the power
(battery) is disconnected from the circuit being measured or tested. 
Existence of power could overload the meter and cause damage to it.
If you are measuring a bulb or a resistor on your hand there is no
power existing on the bulb and resistor. If you measure them in circuit
better make sure power is turned off.

The 2nd mistake is to measure current (amperage) across two points
in the circuit where there is a voltage difference between the two.
It would be a short circuit to the two points by connecting the test
leads of an AMP meter on them. This will cause damage to the meter
and possibly to the circuit being measured.

If the meter is set to voltage measurement mode you can measure
any two points in any circuit with power on. Set the meter to a proper
range for the measurement. Nothing could be damaged.

Just in case you have no idea about these stuff. They may not be
obvious even in good learning books.

David
 
> > 
> > On 8/6/07, Anthony Egeln <regnsuzanne@yahoo.com>
> > wrote:
> > > After reading all the posts on solar power, I now
> > realize that I know shockingly little about
> > electricity.....don't know an amp from a watt from
> a
> > volt.  Can someone who knows about such things please
> > recommend a good, easy-to-read book that would be an
> > electrical primer.  I want to learn about electricity
> > not just for solar applications but also home and auto
> > applications.  At some point I'd like to be able
> to do
> > all these vanagon electrical tests myself and even
> wire my
> > future retirement home.